The correct answer is option 1 - Light sensitive cell. Light sensitive cells, also known as photoreceptor cells, are specialized cells in the retina of the eye that respond to light and convert it into electrical signals. These cells are essential for vision as they transmit the electrical signals to the optic nerve, which then carries the signals to the brain for further processing and interpretation. The two types of light-sensitive cells are called rods and cones. Rods are responsible for detecting shades of gray and are more sensitive in low light conditions, while cones detect colors and work best in bright light. When light enters the eye and reaches the retina, the photoreceptor cells get activated and generate electrical signals, initiating the process of vision.